A unit pump with an actuator carrier and an actuator carrier thereof

ABSTRACT

An actuator carrier comprises an aperture being adapted to receive actuator and a bore being adapted to carry high pressure fluid through the carrier. The actuator carrier can be incorporated into a unit pump allowing for a more efficient design and manufacture process, including linear alignment of all of the unit pumps primary components.

TECHNICAL FIELD

[0001] The present invention is directed to unit pumps and specifically actuator carriers.

BACKGROUND

[0002] Engine manufacturers are constantly striving to become more efficient in their design and manufacture of engine components. One area in particular in which manufacturers have strived to become more efficient is the design of unit pumps. Unit pumps must pressurize fuel to injection pressure levels and deliver that fuel to an injector. One of the concerns with unit pumps is the packaging size or area/volume that the unit pump requires in the engine. It is desirable to have the unit pump be as small as possible. Further, it is desirable to make the manufacturing process as simple as possible to reduce manufacturing time and cost.

[0003] In the past unit pumps have not been designed as efficiently as possible due to the desire to keep high pressure fluid away from the pump's electronics. For example, some unit pumps use a horizontal spill valve with an actuator that is not incorporated into the body of the unit pump. This results in more complicated manufacturing process as well as an increased packaging size. In another type of unit pump design, the solenoid and the fuel line are both offset outside the pump body at one end of the unit pump; again requiring a more complicated manufacturing process and a larger packaging size.

[0004] The present invention is directed to addressing one or more of the above problems.

SUMMARY OF THE INVENTION

[0005] In a first embodiment for the present invention, an actuator carrier comprises a carrier with an aperture being adapted to receive an actuator and a bore adapted to carry high pressure fluid through the carrier. In a second embodiment of the present invention, a unit pump comprises a tappet movable between a first position and a second position, a spring positioned adjacent to the tappet and being adapted to return the tappet to its first position, a fuel cavity, a plunger attached to the tappet and movable between a third and a fourth position within a fuel cavity and being adapted to pressurize fuel within the fuel cavity, spill valve to control the flow of fuel leaving the fuel cavity, an actuator carrier with an aperture adapted to receive an actuator and a bore adapted to carry pressurized fuel from the fuel cavity through the actuator carrier, and a fuel line fitting.

[0006] In yet another embodiment of the present invention, a unit pump comprises a tappet movable between the first position and a second position, a spring positioned adjacent to the tappet and being adapted to return tappet to its first position, a fuel cavity, a plunger attached to the tappet and movable between the third and fourth position within said fuel cavity and being adapted to pressurize fuel in the fuel cavity, a spill valve to control the flow of fuel leaving the fuel cavity, an actuator to control the spill valve, and a substantially linear alignment for the tappet, spring, fuel cavity, plunger, spill valve, an actuator.

BRIEF DESCRIPTION OF DRAWINGS

[0007]FIG. 1 is a diagrammatic isometric cross section of a unit pump incorporating the present invention.

[0008]FIG. 2 is a diagrammatic isometric view of one embodiment of the present invention.

DETAILED DESCRIPTION

[0009] In FIG. 1 a diagrammatic cross section of a unit pump 10 is illustrated. A tappet carrier 12 is attached to a roller 14 by a pin 16. The tappet is moved by a cam (not shown) from the cam shaft (not shown). The tappet carrier 12 contacts plunger 18 which is slidably moveable in fuel cavity 22. A plunger return spring 20 is positioned within the tappet carrier 12 to return the plunger to its original position after the cam (not shown) has passed.

[0010] A tappet sleeve 48 surrounds the tappet carrier 12, plunger return spring 20, and part of plunger 18. The fuel cavity 22 is located within body 46 of the unit pump 10. A spacer/seal 32 fits between body 46 and valve body 24, which is located within a bore of body 46. The valve body 24 contains a spill valve 30 which controls the flow of pressurized fuel from fuel cavity 22. An actuator 28, located in carrier 26, controls the opening and closing of spill valve 30. Actuator 28 could be selected from a variety of actuators well know in the art, including a solenoid, piezo, or other electromagnetic actuator. Spill valve 30 is biased in a first position by return spring 52. In the first position, fuel from fuel cavity 22 is open to the low pressure fill/spill line 54, such that pressurized fuel is actually not created but is instead directed out of the injector. When actuator 28 is energized, spill valve 30 is moved to a second position, against the force of the return spring 52, which closes the fill/spill line 54 and allows the fuel to be pressurized.

[0011] When fill/spill line 54 is closed, high pressure fuel is transferred through the unit pump 10 from the fuel cavity 22 to the fuel line fitting 44 through the seal 32, valve body high pressure passage 36, located in body 46, the carrier high pressure passage 38, located in carrier 26, and the adapter high pressure passage 42, located in adapter 40.

[0012] The flange 34 is part of body 46 and allows the unit pump 10 to be clamped to an engine (not shown) or other base.

[0013]FIG. 2 is a diagrammatic isometric view of the carrier 26. The carrier 26 includes an aperture 50 which is adapted to receive an actuator 28, which is preferably a solenoid but could be any type of mechanical or electrical actuator, including a piezo. The carrier 26 also has a bore, which is high pressure fluid passage 38, which allows high pressure fluid to pass through carrier 26 without contacting actuator 28.

[0014] Carrier 26 must also have sealing surfaces to prevent leakage between carrier 26 and valve body 24 and adapter 40. Additionally, carrier 26 could have small dowel holes adapted to receive a dowels for positioning, assembly and to prevent rotation within unit pump 10.

Industrial Applicability

[0015] The unit pump's primarily purpose is to pressurize fuel for injection into a combustion chamber. The unit pump's 10 roller 14 comes into contact with a cam (not shown). As the cam passes, it moves roller 14, which is attached to the tappet carrier 12, causing plunger 18 to move within fuel cavity 22 and pressurize the fuel located in the fuel cavity 22. Once the cam has passed its maximum lift, the plunger returns spring 20 returns the plunger 18 and tappet carrier 12 to their original positions.

[0016] Pressurized fuel from the fuel cavity 22 moves to the valve body 24 where the spill valve 30 regulates the flow. Spill valve 30 is controlled by actuator 28 located in carrier 26. Spill valve 30 is biased in a first position by a return spring 52, such that fill/spill line 54 is open. If fuel injection is not desired, actuator 28 is not energized, leaving fill/spill line 54 open such that pressurized fuel is not created. In the open position, fuel from fuel cavity 22 is free to flow out of the low pressure fill/spill line 54. However, when actuator 28 is energized, spill valve 30 is moved to a second position, against the force of return spring 52, closing the fill/spill line 54. This allows pressurized fuel to be created by closing the drain path, fill/spill line 54. Fuel from fuel cavity 22 then travels through the valve body high pressure passage 36 to the carrier high pressure passage 38, the adapter high pressure passage 42 and on to the fuel line fitting 44 where the fuel is then transferred to a fuel line (not shown) going to a fuel injector which subsequently injects the fuel into the combustion cylinder (not shown). Note that carrier 26 must provide sealing surfaces between the valve body 24 and adapter 40 to prevent loss of fluid and prevent fluid from contacting the actuator. When it is desired to stop injection, actuator 28 is de-energized, causing return spring 52 to move spill valve 30 back to its first position and opening low pressure fill/spill line 54.

[0017] One key aspect of the unit pump 10 is the design of the carrier 26. Specifically, carrier 26 has an aperture and a bore. The aperture is an actuator cavity 50 which positions an actuator 28, such as a solenoid, within the unit pump body 26. The bore is a high pressure fluid passage 38 which allows pressurized fuel to move through the unit pump 10 and around actuator 28. By incorporating a carrier that can both hold the actuator 28 and provide fluid passage by means of carrier high pressure passage 38, the unit pump's overall package size is substantially reduced. Package size is reduced specifically by packaging the actuator within the unit pump body 46 but still being able to route high pressure fluid through the carrier 26 without leakage. Carrier 26 also reduces the number components need for manufacture by streamlining the design, thereby reducing manufacturing time and cost.

[0018] The carrier 26 allows for substantially linear alignment of the unit pump 10 by combining the actuator 28 and high pressure passage 38 into one piece. Specifically, the roller 14, tappet carrier 12, plunger 18, spill valve 30, actuator 40 can be assemble on or close to the same axis. This again allows for a reduced package size and ease of manufacturing.

[0019] Other aspects, features, and advantage of the present invention may be obtained from a study of this disclosure and drawings, along with the appended claims.

LIST OF ELEMENTS

[0020] TITLE: A Solenoid Carrier with a High Pressure Passage

[0021] FILE: 01-261

[0022] 10 Unit Pump

[0023] 12 Tappet Carrier

[0024] 14 Roller

[0025] 16 Pin

[0026] 18 Plunger

[0027] 20 Plunger Return Spring

[0028] 22 Fuel Cavity

[0029] 24 Valve Body

[0030] 26 Carrier

[0031] 28 Actuator

[0032] 30 Spill Valve

[0033] 32 Spacer/Seal

[0034] 34 Flange/Hold Down Clamp

[0035] 36 Valve Body High Pressure Passage

[0036] 38 Carrier High Pressure Passage

[0037] 40 Adapter

[0038] 42 Adapter High Pressure Passage

[0039] 44 Fuel Line Fitting

[0040] 46 Body

[0041] 48 Tappet Sleeve

[0042] 50 Aperture

[0043] 52 Return Spring

[0044] 54 Fill/spill Line 

What is claimed is:
 1. A unit pump comprising: a tappet moveable between a first position and a second position, a cam being adapted to come in contact with said unit pump and move said tappet between said first and said second position; a spring connected to bias said tappet in said first position; a pump body having a fuel cavity; a plunger connected to said tappet and at least partially disposed in said fuel cavity and being moveable between a third position and a fourth position within said fuel cavity, said plunger being adapted to pressurize fuel in said fuel cavity; a spill valve disposed within said pump body; said spill valve adapted to control a flow of fuel from said fuel cavity; an actuator carrier having an aperture; an actuator disposed in the said aperture and being adapted to actuate said spill valve; a bore disposed in said actuator carrier and being adapted to pass said pressurized fuel from said fuel cavity through said actuator carrier; and a fuel line fitting.
 2. The unit pump of claim 1 wherein said solenoid carrier is metallic.
 3. The unit pump of claim 1 wherein said solenoid carrier's said bore communicates between a first surface of said carrier and a second surface of said carrier.
 4. The unit pump of claim 3 wherein said first and second surfaces are adapted to seal with adjacent components.
 5. The unit pump of claim 1 further comprising dowel holes for positioning said carrier and preventing rotation.
 6. The unit pump of claim 1 wherein said tappet, said spring, said fuel cavity, said plunger, said spill valve, and said actuator carrier, are substantially linearly aligned.
 7. The unit pump of claim 1 wherein said spill valve is aligned linearly with said unit pump.
 8. The unit pump of claim 1 wherein said actuator is a solenoid.
 9. A unit pump comprising: a tappet moveable between a first position and a second position, a cam being adapted to come in contact with said unit pump and move said tappet between said first and said second position; a spring connected to bias said tappet in said first position; a pump body having a fuel cavity; a plunger connected to said tappet and at least partially disposed in said fuel cavity and being moveable between a third position and a fourth position within said fuel cavity, said plunger being adapted to pressurize fuel in said fuel cavity; a spill valve disposed within said pump body; said spill valve adapted to control a flow of fuel from said fuel cavity; an actuator being adapted to actuate said spill valve; wherein said tappet, said spring, said fuel cavity, said plunger, said spill valve, and said actuator, are substantially linearly aligned.
 10. An actuator carrier comprising: a carrier having an aperture, said aperture adapted to receive an actuator; and a bore; said bore being adapted to carry high pressure fluid through said carrier with contacting said actuator.
 11. The actuator carrier of claim 10 wherein said carrier is metallic.
 12. The actuator carrier of claim 10 wherein said bore communicates between a first surface of said carrier and a second surface of said carrier.
 13. The actuator carrier of claim 12 wherein said first and second surfaces are adapted to seal with adjacent components.
 14. The actuator of claim 13 wherein said first surface is adapted to seal with a valve body and said second surface is adapted to seal with an adapter.
 15. The actuator carrier of claim 10 further comprising dowel holes for positioning said carrier and preventing rotation.
 16. The actuator carrier of claim 10 wherein said actuator is a solenoid. 